خيارات البحث
النتائج 5341 - 5350 من 6,560
A review: application of remote sensing as a promising strategy for insect pests and diseases management النص الكامل
2020
Abd El-Ghany, Nesreen M. | Abd El-Aziz, Shadia E. | Marei, Shahira S.
The present review provides a perspective angle on the historical and cutting-edge strategies of remote sensing techniques and its applications, especially for insect pest and plant disease management. Remote sensing depends on measuring, recording, and processing the electromagnetic radiation reflected and emitted from the ground target. Remote sensing applications depend on the spectral behavior of living organisms. Today, remote sensing is used as an effective tool for the detection, forecasting, and management of insect pests and plant diseases on different fruit orchards and crops. The main objectives of these applications were to collate data that help in decision-making for insect pest management and decreasing the environmental pollution of chemical pesticides. Airborne remote sensing has been a promising and useful tool for insect pest management and weed detection. Furthermore, remote sensing using satellite information proved to be a promising tool in forecasting and monitoring the distribution of locust species. It has also been used to help farmers in the early detection of mite infestation in cotton fields using multi-spectral systems, which depend on color changes in canopy semblance over time. Remote sensing can provide fast and accurate forecasting of targeted insect pests and subsequently minimizing pest damage and the management costs.
اظهر المزيد [+] اقل [-]Boosting the catalytic activity of natural magnetite for wet peroxide oxidation النص الكامل
2020
Álvarez-Torrellas, Silvia | Munoz, Macarena | Mondejar, Victor | de Pedro, Zahara M. | Casas, Jose A.
This work explores the modification of naturally occurring magnetite by controlled oxidation (200–400 °C, air atmosphere) and reduction (300–600 °C, H₂ atmosphere) treatments with the aim of boosting its activity in CWPO. The resulting materials were fully characterized by XRD, XPS, TGA, TPR, SEM, and magnetization measurements, allowing to confirm the development of core-shell type structures. The magnetite core of the solid remained unchanged upon the treatment whereas the Fe(II)/Fe(III) ratio of the shell was modified (e.g. 0.42, 0.11 and 0.63 values were calculated for pristine Fe₃O₄, Fe₃O₄-O400, and Fe₃O₄-R400, respectively). The performance of the catalysts was tested in the CWPO of sulfamethoxazole (SMX) (5 mg L⁻¹) under ambient conditions and circumneutral pH (pH₀ = 5), using the stoichiometric dose of H₂O₂ (25 mg L⁻¹) and a catalyst load of 1 g L⁻¹. The key role of the ferrous species on the mineral shell was evidenced. Whereas the oxidation of magnetite led to significantly slower degradation rates of the pollutant, its reduction gave rise to a dramatic increase, achieving the complete removal of SMX in 1.5 h reaction time with the optimum catalyst (Fe₃O₄-R400) compared to the 3.5 h required with the pristine mineral. A reaction mechanism was proposed for SMX degradation, and a kinetic equation based on the Eley-Rideal model was accordingly developed. This model successfully fitted the experimental results. The stability of Fe₃O₄-R400 was evaluated upon five sequential runs. Finally, the versatility of the catalytic system was proved in real environmentally relevant water matrices.
اظهر المزيد [+] اقل [-]Mechanism study of enhanced interaction between gaseous elemental mercury and hydroxylated UIO-66 النص الكامل
2020
Zhou, Changsong | Zhu, Wenxin | Chang, Xiong | Ding, Ding | Zhang, Tingting | Chen, Jiamin | Wu, Hao | Yang, Hongmin | Sun, Lushi
Novel hydroxylated UIO-66 for gaseous elemental mercury (Hg⁰) removal has been considered to be an emerging method because of its economical and reusable property. Density functional theory studies were investigated to reveal the enhanced heterogeneous interaction mechanisms between mercury and hydroxylated UIO-66 with and without the presence of H₂O₂ vapor. The adsorption and dissociation of H₂O₂ and the generation mechanism of surface hydroxyls on UIO-66 were investigated. Results indicated that H₂O₂ preferred to disconnect the O–O bond followed by the generation of two hydroxyls in the presence of H₂O₂. The hydroxyl adsorbed on UIO-66 and formed the UIO-66 hydroxylation product. The interaction performances between Hg⁰, H₂O₂, and UIO-66 as well as the interaction performances between Hg⁰ and hydroxylated UIO-66 systems were both evaluated through binding energy and the Mulliken charge analysis. Interacted energies indicated thermodynamically favorable processes of Hg–OH formation on hydroxylated UIO-66. The Mulliken charge changes revealed an oxidative process of mercury.
اظهر المزيد [+] اقل [-]The effects of a short-term exposure to propiconazole in zebrafish (Danio rerio) embryos النص الكامل
2020
Zhao, Feng | Cao, Fangjie | Li, Hui | Teng, Miaomiao | Liang, Yong | Qiu, Lihong
Propiconazole (PCZ) is a widely used fungicide around the world and was frequently detected in surface waters, which would pose risk to aquatic organisms. Previous studies indicated that PCZ has high toxicity to different kinds of fish. However, most of the studies focus on the toxicity and mechanisms of PCZ to adult fish, the potential toxicity mechanism of PCZ to fish embryos is still poorly understood. The present study investigated the effects of PCZ on content of reactive oxygen species (ROS) and malondialdehyde (MDA); activities of superoxide dismutase (SOD), catalase (CAT), and Na⁺-K⁺-ATPase; and expression level of genes related to oxidative stress, cell apoptosis, and innate immune system in zebrafish embryos after 96-h exposure. The results showed that 5.0 mg/L PCZ induced oxidative damage in zebrafish embryos, as indicated by increased ROS and MDA content and alteration of antioxidative enzyme activity. The activity of Na⁺-K⁺-ATPase in zebrafish embryos was significantly inhibited after exposure to 0.5 mg/L PCZ. The expression levels of bax, p53, casp-3, casp-9, and apaf-1 were significantly increased, indicating that cell apoptosis was caused in embryos by 5.0 mg/L PCZ. The expression level of interleukin-1b (IL-1b) and IL-8 increased after exposure to 0.5 mg/L PCZ, but that of IL-1b, IL-8, and cxcl-c1c (chemokine (C-X-C motif) ligand 18b) decreased in 5.0-mg/L PCZ treatment group, indicating an immunotoxicity effect. Our results suggest that oxidative damage, cell apoptosis, and immunotoxicity would be induced in zebrafish embryos after short-term exposure to PCZ.
اظهر المزيد [+] اقل [-]Investigation of particulate matter by FTIR, TEM and elemental analyses in a diesel engine operating on diesel and waste cooking oil-biodiesel النص الكامل
2020
Ulusoy, Yahya
This study investigated the use of a blend of waste vegetable oil and diesel fuel in a diesel tractor engine by comparing the resulting particulate matter (PM) collected on a filter with the PM of diesel fuel. To this purpose, Fourier transform infrared (FTIR) and elemental analyses were carried out and the PM collected on the filters was examined via scanning electron microscopy (SEM). The study also investigated the overall morphology of soot particles from the blend of 75% waste cooking oil (WCO) + 25% diesel (B75) in a diesel engine at three different loads (75%, 50% and 10%) compared with the morphology of the soot particles from diesel fuel (B0). The FTIR spectra of the B75 fuel exhibited the characteristic regions of oxygen bonds. Compared to the B0 fuel, the increased oxidation from the excess oxygen in the B75 fuel reduced the size and number of soot particles. It was also verified that the degree of unsaturation was related to the oxygen content of the B75 fuel. The FTIR spectra of the B75 fuel showed a C = O tensile band methyl ester in 1734 cm⁻¹ and C–O bands at 1214–1362 cm⁻¹. Furthermore, similar FTIR spectra were seen for the diesel fuel (B0) and the B75 fuel. The results showed a significant reduction in soot particle emissions with the WCO-diesel blend. The results of this research have enabled a better evaluation of the effects of different fuel usage on diesel engine combustion performance and emission characteristics.
اظهر المزيد [+] اقل [-]17α-ethynylestradiol (EE2) limits the impact of ibuprofen upon respiration by streambed biofilms in a sub-urban stream النص الكامل
2020
McClean, Peter | Hunter, William Ross
Pharmaceutical compounds such as the non-steroidal anti-inflammatory drug ibuprofen and the artificial estrogen 17α-ethynylestradiol (EE2) are contaminants of emerging concern in freshwater systems. Globally, human pharmaceutical use is growing by around ~ 3% per year; yet, we know little about how interactions between different pharmaceuticals may affect aquatic ecosystems. Here, we test how interactions between ibuprofen and EE2 affect the growth and respiration of streambed biofilms. We used contaminant exposure experiments to quantify how these compounds affected biofilm growth (biomass), respiration, net primary production (NPP) and gross primary production (GPP), both individually and in combination. We found no effects of either ibuprofen or EE2 on biofilm biomass (using ash-free dry mass as a proxy) or gross primary production. Ibuprofen significantly reduced biofilm respiration and altered NPP. Concomitant exposure to EE2, however, counteracted the inhibitory effects of ibuprofen upon biofilm respiration. Our study, thus, demonstrates that interactions between pharmaceuticals in the environment may have complex effects upon microbial contributions to aquatic ecosystem functioning.
اظهر المزيد [+] اقل [-]Synergetic effect between adsorption and photodegradation on rGO/TiO2/ACF composites for dynamic toluene gaseous removal النص الكامل
2020
Li, Yuwei | Liu, Fang | Li, Meng | Wang, Xuye | Qi, Xuejin | Li, Wei | Siuvai, Ming | Wang, Yongqiang | Han, Fenglei
The toluene poses a serious threat to the atmospheric environment and human health. Herein, the reduced graphene oxide (rGO)/TiO₂ immobilized on the activated carbon fiber (ACF) are fabricated by ultrasonic assisted sol-gel impregnation method to photodegrade dynamic toluene. Characterizations of rGO/TiO₂/ACF composites reveal that the majority of graphene oxide (GO) is reduced to rGO and rGO/TiO₂ is evenly loaded onto the ACF surface in the form of a smooth film. Furthermore, the photoelectrochemical experiments demonstrate both rGO and ACF can enhance significantly the separation efficiency of electron-hole pairs. The maximum removal efficiency of rGO/TiO₂/ACF-0.75% can be up to 85% under ultraviolet irradiation. The rGO/TiO₂/ACF exhibits more excellent adsorption and photodegradation activity for dynamic toluene than both rGO/TiO₂ and ACF due to the synergetic effect rather than a simple linear combination of the rGO/TiO₂ and ACF for toluene conversion. The possible photodegradation pathway is proposed according to intermediates measured by GC-MS, and adsorption coupling photocatalytic mechanisms are discussed.
اظهر المزيد [+] اقل [-]Bio-removal of Pb, Cu, and Ni from solutions as nano-carbonates using a plant-derived urease enzyme–urea mixture النص الكامل
2020
Abdel-Gawwad, Hamdy A. | Hussein, Hala. S. | Mohammed, Mona S.
This study focuses on utilizing a plant-derived urease enzyme (PDUE)–urea mixture to remove heavy metals from water as constituents of nano-carbonate minerals. The bio-removal process was conducted by individually mixing PbCl₂, CuCl₂, and NiCl₂ solutions with a PDUE–urea mixture, followed by incubation for 24 h at 23 ± 2 °C. The preliminary results revealed that the proposed method exhibited high Pb removal efficiency (˃ 99%) in a short time (8 h); meanwhile, moderate Cu and Ni removal efficiencies (67.91% and 58.49%, respectively) were obtained at the same incubation time. The concentration of heavy metals (50–200 mM) had an insignificant effect on the bio-removal rate, indicating that the PDUE–urea mixture is highly effective for the removal of heavy metals at different concentrations. The bio-removal process involved the transformation of soluble heavy metals into insoluble carbonate materials. A spherically shaped nano-cerussite (4–15 nm), a malachite hexahydrate nanosheet (thickness 8 nm), and an ultrafine micro-hellyerite (thickness 0.3 μm) were the main minerals produced by the Pb, Cu, and Ni bio-removal processes, respectively. As a beneficial application, nano-cerussite was used as an additive in an alkali-activated slag/ceramic waste-based geopolymeric coating. A preliminary study proved that increasing the nano-cerussite content enhanced the resistance of the geopolymeric coating to sulfur-oxidizing bacteria, which is detrimental to normal concrete, particularly in sewer systems.
اظهر المزيد [+] اقل [-]Maternal urinary bisphenol A concentration and thyroid hormone levels of Chinese mothers and newborns by maternal body mass index النص الكامل
2020
Wang, Xia | Tang, Ning | Nakayama, Shoji F. | Fan, Pianpian | Liu, Zhiwei | Zhang, Jun | Ouyang, Fengxiu
Animal studies indicated that bisphenol A (BPA) exposure during pregnancy may disrupt thyroid function which is critical for fetal development. However, few epidemiological studies have examined this topic and the results were inconsistent. We aimed to evaluate whether prenatal BPA exposure is associated with thyroid hormone levels in Chinese mothers and newborns with stratification by maternal body mass index (BMI). BPA concentration were measured in urine samples collected from 555 women at late pregnancy. Maternal serum free thyroxin (FT4), thyroid-stimulating hormone (TSH) and thyroid peroxidase antibody (TPO-Ab) concentrations at the third trimester were abstracted from medical records. Cord serum-free triiodothyronine (FT3), FT4, TSH, and TPO-Ab levels were measured in 398 newborns. Prenatal urinary BPA was detected in 98.5% of mothers with a geometric mean of 1.32 ng/mL (95% CI 1.17–1.49 ng/mL). With each 10-fold increase in BPA concentrations, maternal log10_(TSH) mIU/L was 0.10 lowered (95% CI − 0.20, − 0.005, p < 0.05) among pre-pregnancy BMI > 23 kg/m², with adjustment for maternal age, maternal education, gestation diabetes mellitus (GDM), husband smoking during pregnancy, parity, and gestational age at thyroid parameters measured, but no association was observed in pre-pregnancy BMI < 18.5, or 18.5–22.9 kg/m² stratum. No BPA-associated changes were observed in maternal FT4 level or odds of positive TPO-Ab in all BMI stratum. Also, no associations were observed between prenatal urinary BPA concentration and cord serum FT4, FT3, TSH levels, and odds of positive TPO-Ab in both male and female newborns among pre-pregnancy BMI < 18.5, 18.5–22.9 or > 23 kg/m² stratum. In this study, prenatal urinary BPA concentration was associated with lower maternal TSH among women with overweight, but not associated with other maternal thyroid parameters or cord serum thyroid parameters across maternal BMI categories. More research on pregnant women and newborns cohort with BPA exposure are warranted.
اظهر المزيد [+] اقل [-]Determination of nest occupation and breeding effect of the white stork by human-mediated landscape in Western Poland النص الكامل
2020
Bialas, Joanna T. | Dylewski, Łukasz | Tobolka, Marcin
Choosing an appropriate nest site is essential for successful breeding. Changes in land use cause populations of many species to decline although some species adapt to anthropogenic changes. The white stork Ciconia ciconia commonly uses artificial nest sites. Recently, white storks from Western Europe have been using landfills as feeding sites; the beginnings of this process are being observed in Central-Eastern Europe. The study aimed to determine factors influencing the probability of nest occupation and breeding effect in a Central-Eastern European population of white storks. We used long-term data from Western Poland on breeding effect, nest occupation, the structure supporting the nest, the proximity of the nearest landfills, landfill area, and land cover. The probability of nest occupation was significantly dependent on habitat quality (based on the share of the preferred type of land cover), the structure supporting the nest, and landfill proximity within a specific year. The breeding effect was influenced by habitat quality and nesting structure. We demonstrate that the type of nesting structure is an important factor influencing both the probability of nest reoccupation and breeding effect. However, the significance of landfills appears to be growing, and in recent years, storks prefer occupying nests closer to landfills, which may have significant consequences for the population of the white stork.
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